Abstract
Chalky rice is not accepted by rice industry because of its appearance and brittleness. At
present, many people are suffered for celiac disease so they have to avoid consuming foods
with gluten. Rice flour can be used as a main ingredient for many Asian food products.
It gives high energy, mostly from carbohydrate. The objectives of this study were to develop
calcium enriched gluten free pasta by extrusion technology and to improve the pasta
qualities. Four types of hydrocolloid (carboxy methyl cellulose; CMC, propylene glycol
alginate; PGA, xanthan gum; XG and modified xanthan gum; MXG) were used in this study.
The result indicated that 3.00% (w/w flour) MXG was not enough to form pasta dough,
whereas a small amount (0.50%) of CMC, PGA or XG could form pasta shape with a
laboratory-scale pasta extruder. By a pilot-scale twin screw extruder, only 0.30% of CMC,
PGA or XG was needed to strengthen the pasta’s firmness. Enhanced color could be obtained from a mixture of chalky rice flour and yellow corn flour at ratio of 70:30. Lightness (L*), redness (a*) and yellowness (b*) values of the fresh and cooked pasta was 54.52-73.76, 2.08-8.27 and 28.34-47.25, respectively. When adding calcium to the dry mixed flours, L*, a* and b* values of the extruded pasta were significantly decreased (p≤0.05). The formulation of pasta with 0.91% calcium and 0.30% PGA had the superior quality, compared to those with XG and CMC. It had the optimum cooking time of 12.67±0.29 min, the lowest cooking loss (9.20±0.70%), and the highest water absorption (62.96±3.81%). Water activity of fresh and dried pasta was 0.985±0.002 and 0.767±0.058, respectively. Firmness was 8.92±0.62 N. Sensory evaluation revealed that overall liking scores (6.88-7.14) of the pasta enriched with calcium at 20.00% and 50.00% Thai RDI (0.91% and 2.28%, respectively) were not significantly different (p>0.05). By using extrusion process, the calcium enriched gluten-free pasta could be easily scale-up to the industrial scale due to technology availability. Moreover, unwanted chalky rice could be used as a main ingredient of the rice pasta, leading to economical aspect to the rice industry.
